Surface plasmon resonance is a breakthrough in high-throughput protein
interaction analysis. Aiding researchers in a host of fields, the technology
is real time, non-invasive, and above all, accurate.

Biacore® technology, launched by Sweden-based Biacore AB (formerly
Pharmacia Biosensor AB) in 1990 (patent published in 1996), is helping
improve the productivity and cost efficiency of drug discovery and development.
As a result, a number of fields, such as pharmaceutics and biotechnology,
are reaping the benefits.

The technology is useful in many ways. To take one example, it’s
vital for researchers attempting to understand the causes of diseases,
and by aiding early on with research aiming to determine the most viable
drugs for subsequent development, it’s very much a tool of efficiency.

Behind the innovation were three of the company’s employees –
Magnus Malmqvist, Robert Karlsson and Inger Rönnberg. Today Karlsson
is Biacore AB’s Systems and Application Director, while Rönnberg
is the firm’s Project Leader. Malmqvist has since moved on to Bioventia
Capital AB, an international consultancy company, where he is CSO.

The key function of the technology – which is based on the transfer
of light energy (photons) to a group of electrons (a plasmon) in a metal
surface – is its production of real-time measurements of a molecular
interaction in the form of a sensorgram (a graph) produced using surface
plasmon resonance (SPR). The target molecule is bound to the surface of
a gold-coated sensor chip, and a solution containing the test material
is passed over the sensor chip.

The plasmons in the gold chip surface interact (or come in resonance)
with light at a characteristic angle that depends on the molecular composition
on the gold surface. Because the binding process increases the angle where
the light comes in resonance, any binding to the target molecule by a
molecule in the test solution is detected and measured in real time. When
the molecules detach, the angle falls.

SPR sensors in protein interaction dates back to 1983, but it wasn’t
until Malmqvist and his colleagues came up with their invention that high
throughput analysis – simultaneous observation of multiple binding
reactions – became viable. The approach of the Swedes is thus innovative
in that no other technology offers as much information from a single system
(e.g., concentration, specificity, kinetics and affinity).

And unlike traditional techniques, Biacore® combines a range of advantages
in a single technology: It does not require chemical labels – which
saves time and reduces misleading results caused by molecular changes
due to sample labelling – and its continuous, real-time measurements
enable even transient interactions to be monitored.

What’s more, samples can now be measured without the need for purification
(thus in their native state), making it faster to achieve high-quality
results by preserving the protein’s three-dimensional structure
and its in vivo (natural) function. And because the measurement process
is not performed by light absorption and is therefore non-invasive, light-sensitive,
opaque or coloured samples can also be analysed, enabling direct measurement
from patients’ blood samples in clinical drug trials.

The launch of Biacore® coincided with the discovery of the first monoclonal
(derived from one cell) antibodies, which now figure highly in medical
research and development and as therapeutic agents. To date, more than
4,000 peer-reviewed scientific publications have used Biacore® systems
to study protein interactions.

Among the most important of the Biacore® applications is antibody
analysis, whose market as a whole is currently experiencing rapid growth.
Good news for Biacore AB – a company that started off as a small
business more than 20 years ago and now finds itself in a strong position
to consolidate its role as market leader.

And the numbers certainly tell the story – in terms of revenue,
profits and growth. Fuelled by a record-breaking fourth quarter, Biacore
AB increased its sales by 15 percent last year to more than 60 million
euros, with a net income of 20 million euros.

Reflecting on these rather attractive figures, the three inventors can
say with pride that their patent is playing a key part in the Biacore
AB success story.